Gel insoles with lower heel and toe recesses having thin spring walls

ABSTRACT

A removable insole for insertion into footwear, includes a lower layer made of a viscoelastic gel and including a lower surface, an upper surface, a toe portion, a heel portion and a medial arch portion interconnecting the toe portion and the heel portion, a first recess formed in the lower surface of the toe portion and a second recess formed in the lower surface of the heel portion, each recess having a peripheral side wall and a top wall, a plurality of thin, parallel, spaced apart sinusoidal wave shaped spring walls formed from the viscoelastic gel and connected to the top wall and the peripheral side wall in each recess, and the spring walls having lower edges generally coplanar with a lower surface of the toe portion and heel portion which is in surrounding relation to the respective recess; and a top cover secured to the upper surface of the lower layer.

This application is a continuation of 10/026,571 filed on Dec. 20, 2001now U.S. Pat. No. 6,598,321 which is a continuation of 09/803,706 filedon Mar. 9, 2001 now abandoned which is a continuation of 09/454,980filed Dec. 3, 1999 now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to shoe insoles, and moreparticularly, to improved gel insoles for shoes that provide bothcushioning and spring characteristics.

Insoles have generally been formed by a pad of cushioning material, suchas foam or sponge rubber, that has a general shape conforming to theinterior of a shoe. Wearers who desire additional shoe comfort or whosuffer from foot trouble, for example, plantar heel pain and/or archpain, insert the cushioned insole into the shoe to provide addedcushioning and support.

It is also known to provide gel insoles for shoes. The gel insoles areprovided as a movable fluid or as a viscoelastic gel. Because of theviscous nature of the gel, the gel insoles provide shock absorption andconsequently protection to the foot. One reason that gel insoles arepopular is that they can be made sufficiently thin to fit in shoes. Inorder to provide comfort, a soft, absorbent top cloth is adhered to theupper surface of the gel insoles.

However, the shock absorbing quality of the gel insoles has adeleterious effect. Specifically, because of the dampening affect of thegel, walking can require more energy, causing the muscles to get tiredmore easily.

U.S. Pat. No. 5,551,173 to Chambers discloses an insole having oblongprotuberances on the upper surface and located in areas corresponding tothe reflex zones of the feet, to provide a massaging action thereat. Itis further disclosed in this patent that the insoles can be reversed sothat the protuberances are on the lower surface of the insoles for thepurpose of raising the insoles to provide air circulation. However,because of the composition of the insoles and the shapes of theprotuberances, the protuberances do not substantially aid in reducingthe energy during walking.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a gelinsole that overcomes the problems with the aforementioned prior art.

It is another object of the present invention to provide a gel insolethat provides the shock dampening affect of a gel material, while alsoproviding a spring action push-off for walking.

It is still another object of the present invention to provide a gelinsole that provides comfort to a person's feet, without causing themuscles to tire easily.

In accordance with an aspect of the present invention, a removableinsole for insertion into footwear, includes a lower layer made of aviscoelastic gel and including a lower surface, an upper surface, and atleast one of a toe portion and a heel portion formed from theviscoelastic gel. At least one recess is formed in the lower surface ofthe toe portion and/or heel portion, each recess having a peripheralside wall and a top wall. A plurality of spaced apart spring wallsformed from the viscoelastic gel are provided in each recess, the springwalls being connected with the top wall of the respective recess, andthe spring walls having lower edges generally coplanar with a lowersurface of the toe portion and/or heel portion which is in surroundingrelation to the respective recess. A top cover is secured to the uppersurface of the lower layer.

Preferably, when a recess is formed in the heel portion, each of thespring walls has a height in a first direction which is greater than awidth thereof in a direction transverse to the first direction.

In one embodiment, each of the spring walls is formed in a generallysinusoidal wave shape, with the plurality of spring walls being insubstantially parallel, spaced apart relation. A spacing betweenadjacent ones of the spring walls is greater than the width of thespring walls. Further, the sinusoidal wave shaped spring walls areconnected with the peripheral side wall and the top wall of therespective recess.

In another embodiment, the spring walls are formed as column members, inparallel, spaced apart relation. Each of the column members can have acylindrical shape, a triangular cross-sectional shape, or any othersuitable cross-section. When a recess is formed in the heel portion,each of the spring walls has a height in a first direction which isgreater than a width thereof in a direction transverse to the firstdirection. Also, a spacing between adjacent ones of the spring walls ispreferably greater than the width of the spring walls. The spring wallsare connected with the top wall of the respective recess.

The insole also includes at least one pattern trim line at the toeportion for trimming the insole to fit into smaller size footwear.

Preferably, the lower layer includes the toe portion, the heel portionand a medial arch portion interconnecting the toe portion and the heelportion, with a first recess with the spring walls in the toe portionand a second recess with the spring walls in the heel portion. In suchcase, the heel portion has a greater thickness than the toe portion, andthe spring walls in the second recess having a greater height than thespring walls in the first recess. Also, opposite sides of the medialarch portion and opposite sides and a rear end of the heel portiongently slope downwardly and inwardly toward the lower surface of thelower layer.

The above and other features of the invention will become readilyapparent from the following detailed description thereof which is to beread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a gel insole according to one embodiment ofthe present invention;

FIG. 2 is a bottom plan view of the gel insole;

FIG. 3 is a side elevational view of the gel insole;

FIG. 4 is a cross-sectional view of the gel insole, taken along line 4—4of FIG. 2;

FIG. 5 is a cross-sectional view of the gel insole, taken along line 5—5of FIG. 2;

FIG. 6 is a cross-sectional view of the gel insole, taken along line 6—6of FIG. 2;

FIG. 7 is an enlarged perspective view of a cut-away portion of the thinspring walls at the bottom of the heel, having a sinusoidal wavepattern;

FIG. 8 is an enlarged perspective view of a cut-away portion of thinspring walls at the bottom of the heel of another embodiment of thepresent invention, and having a cylindrical column pattern;

FIG. 9 is a bottom plan view of the cut-away portion of the thin springwalls of FIG. 8;

FIG. 10 is an enlarged perspective view of a cut-away portion of thinspring walls at the bottom of the heel of still another embodiment ofthe present invention, and having a triangular column pattern;

FIG. 11 is a bottom plan view of the cut-away portion of the thin springwalls of FIG. 10;

FIG. 12 is an enlarged perspective view of a cut-away portion of springwalls at the bottom of the heel of yet another embodiment of the presentinvention, and having a hemispherical shape;

FIG. 13 is a bottom plan view of the cut-away portion of spring walls ofFIG. 12;

FIG. 14 is a cross-sectional view of the cut-away portion of FIG. 13,taken along line 14—14 thereof;

FIG. 15 is a cross-sectional view similar to FIG. 14, but showing amodification of the spring walls thereof;

FIG. 16 is a cross-sectional view of a heel portion of a gel insoleaccording to another embodiment of the present invention;

FIG. 17 is a graphical diagram of 25% compression-load-deflection versusdifferent geometries of the spring walls;

FIG. 18 is a graphical diagram of cushioning energy walking versusdifferent geometries of the spring walls; and

FIG. 19 is a graphical diagram of peak impact force versus differentgeometries of the spring walls.

DETAILED DESCRIPTION

Referring to the drawings in detail, and initially to FIGS. 1–7 thereof,an insole 10 according to a first embodiment of the present invention isadapted to be placed in an article of footwear, as is well known.Accordingly, insole 10 has the shape of a human left foot and has acompanion (not shown) for the right foot which is formed in a mirrorimage.

Insole 10 therefore includes a curved toe portion 12, a heel portion 14,and a medial arch portion 16 which connects toe portion 12 and heelportion 14 together. Heel portion 14 has a greater thickness than toeportion 12 since the greater impact during walking and running occurs atthe heel. For example, in the embodiment of FIGS. 1–7, heel portion 14can have a thickness of approximately 7–8 mm and toe portion 12 can havea thickness of approximately 2–3 mm. In addition, opposite sides ofmedial arch portion 16, and opposite sides and the rear end of heelportion 14, gently slope downwardly and inwardly toward the lowersurface of insole 10.

Insole 10 is formed of a lower gel layer 18 and a top cover 20 securedto the upper surface of lower gel layer 18 by any suitable means, suchas adhesive, RF welding, etc. Both layers 18 and 20 are preferablyformed of a fluid impermeable material.

Lower gel layer 18 is made from a non-foam elastomer such as the classof materials known as viscoelastic polymers or silicone gels, which showhigh levels of damping when tested by dynamic mechanical analysisperformed in the range of −50° degrees C. to 100° degrees C. Because themechanical properties of the gel are more viscous than elastic, the gelprovides a high energy absorption. Gels that can be used according tothe present invention are thermoplastic elastomers (elastomericmaterials), such as materials made from many polymeric families,including but not limited to the Kraton family of styrene-olefin-rubberblock copolymers, thermoplastic polyurethanes, thermoplastic polyolefins, polyamides, polyureas, polyesters and other polymer materialsthat reversibly soften as a function of temperature. The preferredelastomer is a Kraton block copolymer ofstyrene/ethylene-co-butylene/styrene or styrene/butadiene/styrene withmineral oil incorporated into the matrix as a plasticizer.

However, as discussed above, because of the dampening affect of the gel,walking can require more energy, causing the muscles to get tired moreeasily.

In this regard, in accordance with an important aspect of the presentinvention, thin and spaced apart elastic and resilient spring walls 22are formed in a repeating order within a recess 24 formed in toe portion12. Recess 24 occupies a substantial central area of toe portion 12,with thin spring walls 22 extending substantially transversely from oneside to the other side of recess 24 and integrally formed as a unitary,one-piece structure with the peripheral side wall 28 and top wall 34 ofrecess 24. The height of spring walls 22 is the same as the height ofrecess 22 so that lower edges of thin spring walls 22 are substantiallycoplanar with the lower surface of insole 10, as shown best in FIG. 5.In the embodiment of FIGS. 1–7, thin spring walls 22 and recess 24 eachhave a height of approximately 1 mm and a thickness or width ofapproximately 1.5 mm, while the height of lower gel layer 18 insurrounding relation to recess 24 has a height of approximately 2 mm andtop cover has a height of approximately 1 mm.

In the embodiment of FIGS. 1–7, thin, spaced apart spring walls 22 areformed as parallel, spaced apart, sinusoidal shaped wave patterns,although the present invention is not so limited, as will be understoodfrom the other embodiments discussed hereinafter. Although fifteentransverse rows of thin spring walls 22 are shown with a spacing ofapproximately 4 mm between adjacent rows, the present invention is notso limited, and this number may vary by changing the amplitude of thesinusoidal wave patterns and/or spacing between the sinusoidal wavepatterns. In addition, the pitch of the sinusoidal wave patterns in thetransverse direction may also be varied.

In like manner, thin elastic and resilient spring walls 36 are formed ina repeating order within a recess 38 formed in heel portion 14. Recess38 occupies a substantial central area of heel portion 14, with thinspring walls 36 extending substantially transversely from one side tothe other side of recess 38 and integrally formed as a unitary,one-piece structure with the peripheral side wall 42 and top wall 48 ofrecess 38. The height of spring walls 36 is the same as the height ofrecess 38 so that lower edges of thin spring walls 36 are substantiallycoplanar with the lower surface of insole 10, as shown best in FIG. 6.In the embodiment of FIGS. 1–7, thin spring walls 36 and recess 38 eachhave a height of approximately 3 mm and a thickness or width ofapproximately 1.5 mm, while the height of lower gel layer 18 insurrounding relation to recess 38 has a height of approximately 9 mm andtop cover has a height of approximately 1 mm.

In the embodiment of FIGS. 1–7, thin, spaced apart spring walls 36 areformed as parallel, spaced apart, sinusoidal shaped wave patterns,although the present invention is not so limited, as will be understoodfrom the other embodiments discussed hereinafter. Although eleventransverse rows of thin spring walls 36 are shown with a spacing ofapproximately 4 mm between adjacent rows, the present invention is notso limited, and this number may vary by changing the amplitude of thesinusoidal wave patterns and/or spacing between the sinusoidal wavepatterns. In addition, the pitch of the sinusoidal wave patterns in thetransverse direction may also be varied.

The reason for providing thin, spaced apart spring walls in recesses 24and 38 of toe portion 12 and heel portion 14, respectively, is thatthese are the areas where the major forces are exerted on insole 10during heel impact and during push off. With this arrangement, the gelmaterial of lower gel layer 12 is more viscous than elastic, whichprovides a high energy absorption by the gel. On the other hand, thinflexible and resilient spring walls 22 and 36 are more elastic thanviscous, which provides a quicker acting spring than the gel of theremainder of lower gel layer 12, but with less dampening energyabsorption. Thus, when a force is applied to thin spring walls 22 and36, the response is more like a spring than as a damper, while the basegel of the remainder of lower gel layer 12 has an opposite response,that is, acting more like a damper than a spring. This combination ofthe more viscous base gel and the more elastic thin spring walls givesinsole 10 a unique feature of a fast reaction on first heel impact and aslower higher damped energy absorption as the heel recedes into theviscous base of insole 10. When the heel recedes from insole 10, thereverse action occurs, that is, thin spring walls 36 return some of thespring action to the heel. When the foot moves to push off, the actionof insole 10 is the same. In other words, this combination of the moreviscous base gel and the more elastic thin spring walls 22 gives insole10 a unique feature of a fast reaction on first forefoot impact and aslower higher damped energy absorption as the forefoot recedes into theviscous base of insole 10. When the forefoot recedes from insole 10, thereverse action occurs, that is, the thin spring walls 22 return some ofthe spring action to the forefoot, giving the foot a softer impact and aspringy push off.

Measurements of the shock-absorbing or cushioning properties of insole10 can be made using any suitable method, such as by using an impacttester and/or a ball rebound tester. An example of a suitable method isdisclosed in “Physical Test Method PM159—Cushioning Properties,” SATRA,June, 1992, pages 1–7.

The latter test is used to determine cushion energy (CE), cushion factor(CF) and resistance to dynamic compression. Cushion energy is the energyrequired to gradually compress a specimen of the material up to astandard pressure with a tensile testing machine. Cushion factor is abulk material property and is assessed using a test specimen greaterthan sixteen millimeters thick. The pressure on the surface of the testspecimen at a predefined loading is multiplied by the volume of the testspecimen under no load. This pressure is then divided by the cushionenergy of the specimen at the predefined load. Lastly, the resistance todynamic compression measures changes in dimensions and in cushion energyafter a prolonged period of dynamic compression.

Tests were performed to measure cushioning energy during walking andrunning in the heel and toe regions of solid gel insoles without thinspring walls according to the prior art and solid gel insoles 10according to the present invention with thin spring walls 22 and 36, andthe results are shown in the following Tables I–IV, were CE is thecushioning energy, that is, a measure of shock absorption and energyreturn, and σ is the standard deviation.

TABLE I Cushioning Energy: Heel Region Men's Gel Insoles CE CE (walking)σ (running) σ prior art 13.1 0.3 42.1 1.2 present 99.6 1.3 194.6 7.8invention (with spring walls)

TABLE II Cushioning Energy: Toe Region Men's Gel Insoles CE CE (walking)σ (running) σ prior art 13.5 0.1 43.0 1.4 present 30.5 1.2 45.8 2.1invention (with spring walls)

TABLE III Cushioning Energy: Heel Region Women's Gel Insoles CE CE(walking) σ (running) σ prior art 14.8 0.7 46.9 1.9 present 58.0 5.0101.0 8.2 invention (with spring walls)

TABLE IV Cushioning Energy: Toe Region Women's Gel Insoles CE CE(walking) σ (running) σ prior art 11.1 0.1 35.2 4.8 present 37.1 0.960.9 1.6 invention (with spring walls)

It will be appreciated from the above that there is a substantialincrease in the cushioning energy of insoles 10 with thin spring walls22 and 36 according to the present invention in comparison withconventional gel insoles that do not include the thin spring walls.

Although thin, spaced apart spring walls 22 and 36 have been shown in asinusoidal wave pattern, such thin spring walls can take other shapes,such as the columnar shape of FIGS. 8 and 9, that is, formed as aplurality of parallel, spaced apart, discrete cylindrical columns 50 ineach recess 24 and 38, with lower edges thereof being substantiallycoplanar with the lower surface of insole 10 in surrounding relation tothe recess, in the same manner as spring walls 22 and 36. In such case,the diameter of each column 50 is preferably much less than the heightof each column, for example, in the ratio of approximately 1:2 to 1:4.

As another alternative embodiment, the thin spring walls can have thecolumnar shape of FIGS. 10 and 11, that is, formed as a plurality ofparallel, spaced apart, discrete columns 52 but with triangularsectional configurations, in each recess 24 and 38, with lower edgesthereof being substantially coplanar with the lower surface of insole 10in surrounding relation to the recess, in the same manner as springwalls 22 and 36. In such case, the length of any triangular side of eachcolumn 52 is preferably much less than the height of each column, forexample, in the ratio of approximately 1:2 to 1:4.

As another alternative embodiment, the thin spring walls can have thehemispherical shape of FIGS. 12–14, that is, formed as a plurality ofspaced apart hemispheric shaped walls 54 in each recess 24 and 38, withlower edges thereof being substantially coplanar with the lower surfaceof insole 10 in surrounding relation to the recess, in the same manneras spring walls 22 and 36. Alternatively, in place of hemisphericalshaped walls 54, the shape can be varied slightly to presentsubstantially conical shaped walls 56 with rounded free ends 58, asshown in FIG. 14.

The different geometries of the spring walls are provided for differentinsoles in order to vary the spring and cushioning effects.

In this regard, FIG. 17 shows a graphical diagram of 25%compression-load-deflection versus different geometries of insole 10 atthe position of the spring walls. This is a static load test that showsthe static support that insole 10 provides for the different geometriesof hemispheric shaped walls 54, triangular column walls 52, cylindricalcolumn walls 50 and sinusoidal wave walls 22, 36. This test measures theforce or load necessary to deflect insole 10 at the plantar surface ofthe foot, and thereby measures the amount of static support that insole10 provides.

The solid line, inverted check mark plot was performed with a gel havinga TPE Shore A hardness of 30. As clearly seen, the best static supportoccurs with cylindrical columns 50. The dashed line plot was performedwith a gel having a TPE Shore A hardness of 3. The best static supportagain occurs with cylindrical columns 50, and the worst static supportoccurs with hemispheric shaped walls 54. The horizontal line atapproximately 14 psi is a comparison line obtained with a plaque orsection of constant urethane foam according to the prior art.

FIG. 18 shows a graphical diagram of cushioning energy walking versusdifferent geometries of the thin spring walls. This is a test of theshock absorption and energy return of insole 10 at the spring walls forthe different geometries of hemispheric shaped walls 54, triangularcolumn walls 52, cylindrical column walls 50 and sinusoidal wave walls22, 36 at the plantar surface of the foot.

The solid line plot was performed with a gel having a TPE Shore Ahardness of 30. As clearly seen, the best spring action occurs with thesinusoidal wave spring walls 22, 36, while the worst spring action againoccurs with hemispheric shaped walls 54. The dashed line plot wasperformed with a gel having a TPE Shore A hardness of 3. The best springaction again occurs with spring walls 22, 36. The horizontal line atapproximately 29 N-mm is a comparison line obtained with a plaque orsection of constant urethane foam according to the prior art.

FIG. 19 shows a graphical diagram of peak impact force versus differentgeometries of insole 10 at the position of the spring walls. This is adynamic load test that shows the dynamic support that insole 10 providesfor the different geometries of hemispheric shaped walls 54, triangularcolumn walls 52, cylindrical column walls 50 and sinusoidal wave walls22, 36. This test measures the ability to absorb shock during walking orrunning at the plantar surface of the foot.

As clearly seen, the different geometries of the spring walls can spreadthe impact forces over a large surface area, thereby decreasing the peakimpact load.

From the above, it is clearly seen that different geometries can beselected for different purposes, that is, to varying the staticcushioning, dynamic cushioning and spring effect.

Top layer 20 can be made from any suitable material such as fabric,leather, leatherboard, expanded vinyl foam, flocked vinyl film,coagulated polyurethane, latex foam on scrim, supported polyurethanefoam, laminated polyurethane film or in-mold coatings such aspolyurethane, styrene-butadiene-rubber, acrylonitrile-butadiene,acrylonitrile terpolymers and copolymers, vinyls, or other acrylics, asintegral top covers. Desirable characteristics of top cover 20 includegood durability, stability and visual appearance. Also desired is thatthe material of top cover 20 have good flexibility, as indicated by alow modulus, in order to be easily moldable. The bonding surface of topcover 20 should provide an appropriate texture in order to achieve asuitable mechanical bond to lower gel layer 12. Preferably, top cover 20is a fabric, such as a brushed knit laminate top cloth (brushed knitfabric/urethane film/non-woven scrim cloth laminate) or a urethane knitlaminate top cloth.

Typically, insole 10 would be sized corresponding to shoe sizes andwould be provided in sized pairs. Alternatively, insole 10 may betrimmed to the requirements of the user. In this regard, arcuate patterntrim lines 58 and 60 may be formed on the lower surface of toe portion12 of insole 10, and which are representative of various sizes of thehuman foot. For example, insole 10 may be provided for a men's shoe sizeof 11–12, with first continuous pattern trim line 58 beingrepresentative of a smaller size insole for a men's shoe size 9–10, andsecond continuous pattern trim line 60 extending around the periphery oftoe portion 12 indicative of another size of insole for a men's shoesize 7–9. If the user requires a size other than the original largesize, the wearer merely trims the insole with a scissors or cuttinginstrument, using pattern trim line 58 or 60, to achieve the propersize. The pattern trim lines may be imprinted by conventional printingtechniques, silkscreening and the like. As an alternative, pattern trimlines 58 and 60 may be formed as shallow grooves, as shown in FIGS. 2and 4, or be perforated, so that a smaller size insole may be separatedby tearing along the appropriate trim lines, which tearing operation isfacilitated by the inclusion of perforations.

Although the present invention has been disclosed relative to a fulllength insole, it will be appreciated that an insole according to thepresent invention can be made other than a full length insole, such as athree quarter length insole, that is, where the length extends from theheel to the first metatarsals of the foot, or any other suitablearrangement.

Further, although heel portion 14 has been shown to have a uniformheight along the entire width thereof, other variations may be provided,as shown in FIG. 16, in which heel portion 14 has sloping side edges andin which the width decreases toward the middle thereof.

Although the present invention uses the term insole, it will beappreciated that the use of other equivalent or similar terms such asinnersole or insert are considered to be synonymous and interchangeable,and thereby covered by the present claimed invention.

Having described specific preferred embodiments of the invention withreference to the accompanying drawings, it will be appreciated that thepresent invention is not limited to those precise embodiments and thatvarious changes and modifications can be effected therein by one ofordinary skill in the art without departing from the scope or spirit ofthe invention as defined by the appended claims.

1. A removable insole for insertion into footwear, comprising a lowerlayer made of a viscoelastic gel and including: a lower surface; anupper surface; at least one of a toe portion and a heel portion formedfrom said viscoelastic gel, at least one recess in the lower surface ofsaid at least one of a toe portion and a heel portion, each said recesshaving a peripheral side wall and a top wall, and a plurality of spacedapart spring walls formed from said viscoelastic gel in each saidrecess, said spring walls being connected with said top wall of arespective said recess, said spring walls having lower edges generallycoplanar with a lower surface of said at least one of a toe portion anda heel portion which is in surrounding relation to the respective saidrecess, wherein each said spring walls consists of a generallysinusoidal wave shape.
 2. A removable insole according to claim 1,wherein, when said at least one recess is formed in the heel portion,each of said spring walls has a height in a first direction which isgreater than a width thereof in a direction transverse to said firstdirection.
 3. A removable insole according to claim 2, wherein saidspring walls are connected with said peripheral side wall and said topwall of the respective said recess.
 4. A removable insole according toclaim 1, wherein said plurality of spring walls are formed insubstantially parallel, spaced apart relation.
 5. A removable insoleaccording to claim 1, wherein, when said at least one recess is formedin the heel portion, each of said spring walls has a height in a firstdirection which is greater than a width thereof in a directiontransverse to said first direction.
 6. A removable insole according toclaim 5, wherein a spacing between adjacent ones of said spring walls isgreater than the width of said spring walls.
 7. A removable insoleaccording to claim 6, wherein said column members are in parallel,spaced apart relation.
 8. A removable insole according to claim 1,wherein said spring walls are formed as column members.
 9. A removableinsole according to claim 8, wherein, when said at least one recess isformed in the heel portion, each of said spring walls has a height in afirst direction which is greater than a width thereof in a directiontransverse to said first direction.
 10. A removable insole according toclaim 8, wherein a spacing between adjacent ones of said spring walls isgreater than the width of said spring walls.
 11. A removable insoleaccording to claim 8, wherein said spring walls are connected with saidtop wall of the respective said recess.
 12. A removable insole accordingto claim 1, further comprising at least one pattern trim line at the toeportion for trimming the insole to fit into smaller size footwear.
 13. Aremovable insole according to claim 1, wherein said lower layer includessaid toe portion, said heel portion and a medial arch portioninterconnecting said toe portion and said heel portion, with a firstsaid recess with said spring walls in said toe portion and a second saidrecess with said spring walls in said heel portion.
 14. A removableinsole according to claim 13, wherein said heel portion has a greaterthickness than said toe portion, and said spring walls in said secondrecess having a greater height than said spring walls in said firstrecess.
 15. A removable insole according to claim 12, wherein oppositesides of said medial arch portion and opposite sides and a rear end ofsaid heel portion gently slope downwardly and inwardly toward the lowersurface of said lower layer.
 16. A removable insole according to claim1, further comprising a top cover secured to the upper surface of saidlower layer.